This is a discussion on 4 pot/2 pot brake caliper upgrade 2008+ wrx within the Suspension and Handling forums, part of the Tutorials & DIY category; Okay guys So here is my write up from the brake upgrade I did on on my 2011 WRX premium ...

4 pot/2 pot brake caliper upgrade 2008+ wrx

Okay guys So here is my write up from the brake upgrade I did on on my 2011 WRX premium sedan. I upgraded the calipers from the sliding type to the fixed caliper 4/2 pot 06-07 wrx oem calipers. This ended up being WAY simpler and easier than I imagined. Ken and Nick at KNS brakes helped me with gathering all the parts necessary for the upgrade. I can not say enough about their service. They were very helpful and professional. They can get you ALL the parts you need for this upgrade. The adapter bracket they make for the rear calipers is what made this upgrade so easy. here it is

The hardest part of this is going to be figuring out where to start. Just break your lugs free and jack the car up completely off the ground and put it on jackstands. I started with the passenger front caliper and made my way around the car. Take all of your wheels off and get all your parts lined up and ready to go.

turn your wheel so you can easily access the caliper and remove the bolts holding it in place. there should be two of them and they will be easily identifiable to you. Crimp your brake line off with a vice grip or something of that nature. I used a towel over the brake line and a vice grip so I didnt accidentally tear the rubber line.

Next you will remove the banjo bolt from the back of the caliper and the two bolts holding the caliper in place. then slide it off. rear caliper just to show it off the car.

Then you simply reverse the process with the new caliper. It can go on the car with the pads and all the hardware already in it. If you need to know how to assemble the caliper and pads google it.

new caliper bolted up.

Once the caliper is bolted into place and the banjo bolt on the brake line is re attached to the caliper you will need to put a dish under the caliper and run a line off of the bleeder. crack the bleeder and let the caliper fill up with brake fluid until it starts to drip. then close the bleeder. if you get any brake fluid on the caliper immediately pour water on it. brake fluid eats paint and water neutralizes it.

move onto the rear and do the same as the front. once you get the caliper free and off the rotor You will need two bolts that thread into the rotor to pull it off the hub. I forget what size they are but you can get them at any hardware store. your new rotor will be a vented rotor from a 2010+ legacy GT. It will fit in the dust shield. some guys say you need to trim it but I did not have to.

take your adapter bracket from KNS and put it on. It will not bolt right up immediately. it is a black bracket and once you try to thread the bolts through it and realize it is not going to work you can take it off and look at the inside of it. you will see some points where it is rubbing and that is where you will need to take a dremel to the hub. no big deal it is hardly any material just do it.

stock rear caliper and rotor.

two bolts I was talking about

what needs to be ground off

KNS adapter installed

new legacy GT rear rotor

caliper on the rear

notice it clears the dust shield by like a mile

now you can continue on with the other side and it will go much smoother since you know what to do. once the calipers are all full with brake fluid you will just need to bleed them. I flushed the entire brake system out and put new dot 4 brake fluid in it. some guys use fancy high tech stuff but I didnt. just regular valvoline dot 4 fluid works just fine. the order you will bleed the brakes is:

passenger side front
driver side rear
driver front
passenger rear

then you are done! no clearance issues! just put your wheels on and be sure to crank your lugs when the car is back on the grond! the whole process only took me and my dad about 3 hours.

If you guys do this upgrade you can pm me with any questions. Hope this helps someone out!

Are the 4 pots that much better than the slider breaks? What's your impression so far?

They are significantly better. If you dont want to pony up and spend the $$$ then maybe some brake lines and pads would suffice. I for one think they stop a hell of a lot better and they look 1,000,000x better than the stock sliders. The car stops on a dime now but I can not say that it is 100% because of the calipers due to the pads and fluid flush that I did when I installed them

subscribed.. I've been looking to do this for a while now. Just have to figure out how to get the GF to think someone else stole the calipers off her 07... lol

But seriously, thanks for posting this. What most dont understand is that this is the regulation brake set up for the rallyX cars. The big brembo's on the STI are outside of group N and production class rules. So I figure if they work well enough for Rallying duties they'll work just fine for a hard driven street car.

OBP 2010 5dr *traded*
SWP 2013 FRS
My name is Shawn, I'm a Devout Practicalist and I'm addicted to flat4's This page has had 1,666 visitsSUCH IS MANGO!

They are significantly better. If you dont want to pony up and spend the $$$ then maybe some brake lines and pads would suffice. I for one think they stop a hell of a lot better and they look 1,000,000x better than the stock sliders. The car stops on a dime now but I can not say that it is 100% because of the calipers due to the pads and fluid flush that I did when I installed them

Looks like an excellent upgrade. I'll also throw my $0.02 in and say that a simple upgrade of pads, fluid, and SS lines made a world of difference on my '09.

I think the "solid improvement" you report is more-so from improved pads and fluid than the brakes themselves. The new 2-pot caliper has a similar pad area compared to the outgoing 4-pot brakes as well as a similar brake disk diameter. The 4 pistons should slightly improve the brake-fade resistance, but you will likely not notice unless tracking the car. Even still, the 4/2s look MUCH better. Let me put it this way: my MS3 with 1-pot calipers at all 4 corners stops as well as my WRX with a 4-piston BBK up front since the pad area is similar.

Why did you do all that work and not replace the brake lines with SS lines?? That's a HUGE improvement in brake feel.

Shawn:

You are correct. The 4/2 "Subaru" brakes are homologated for use in RallyX.

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